Installation, Operation, & Maintenance for CRFF-E Series
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Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
Communication Specification
Overview
•
MODBUS RTU protocol over RS485 (serial).
•
9600 baud rate, word length is 8, parity is none(n), stop bits=1.
•
255 unique address values selectable by DIP switch settings. (Recommended network node capacity 200 nodes.)
•
Slew rate limited transceivers for improved network performance
.
• Do not use crossover cables. This may damage the control card or render it non-operational.
To reset non-volatile registers to factory default values, write 170 (AA hex) to Register 14, then cycle power.
Note: Register 24 may be read in network mode to determine the value of 0-10VDC signal that may be
connected. For example, a pressure transducer may be conected to indicate unit static pressure
MODBUS REGISTER SUMMARY TABLE
1
2
6
9
10
12
14
1
1
RUN/STOP
DEMAND
SPEED
STATUS
DEFAULT SPEED
CURRENT SPEED
DEFAULT RUN/STOP
RW
RW
RW
RW
R
R
R
0-100
0-100
0-100
0,1
0,1
0,5-2000
see detail
%
RPM
50
-
-
RAM
RAM
LIVE
LIVE
LIVE
EEPROM
EEPROM
power up from REG 14
power up from REG 10
applies to network only
applies in network mode only
Register
Name
R/W
Values & Defaults
Units
Origin
Comments
24
7
0-1000
LIVE
-
ANA1
Onboard Pot 0-1000=0-100%
0-1000
LIVE
-
ANA2
0-10V input 0-1000=0-10VDC
R
R
Summary of Contents for CRFF-E
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